20,435 research outputs found
Aerodynamic preliminary analysis system. Part 2: User's manual and program description
A comprehensive aerodynamic analysis program based on linearized potential theory is described. The solution treats thickness and attitude problems at subsonic and supersonic speeds. Three dimensional configurations with or without jet flaps having multiple nonplanar surfaces of arbitrary planform and open or closed slender bodies or noncircular contour are analyzed. Longitudinal and lateral-directional static and rotary derivative solutions are generated. The analysis is implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis problem. Nominal case computation time of 45 CPU seconds on the CDC 175 for a 200 panel simulation indicates the program provides an efficient analysis for systematically performing various aerodynamic configuration tradeoff and evaluation studies
Vacuum-UV negative photoion spectroscopy of CH3F, CH3Cl and CH3Br
Using tunable vacuum-UV radiation from a synchrotron, negative ions are detected by quadrupolar mass spectrometry following photoexcitation of three gaseous halogenated methanes CHX (X = F,Cl,Br). The anions X, H, CX, CHX and CHX are observed, and their ion yields recorded in the range 8-35 eV. The anions show a linear dependence of signal with pressure, showing that they arise from unimolecular ion-pair dissociation, generically described as AB + h A + B (+ neutrals). Absolute cross sections for ion-pair formation are obtained by calibrating the signal intensities with those of F from both SF and CF. The cross sections for formation of X + CH are much greater than for formation of CHX + H. In common with many quadrupoles, the spectra of / 1 (H) anions show contributions from all anions, and only for CHBr is it possible to perform the necessary subtraction to obtain the true H spectrum. The anion cross sections are normalised to vacuum-UV absorption cross sections to obtain quantum yields for their production. The appearance energies of X and CHX are used to calculate upper limits to 298 K bond dissociation energies for D (HC-X) and D (XHC-H) which are consistent with literature values. The spectra suggest that most of the anions are formed indirectly by crossing of Rydberg states of the parent molecule onto an ion-pair continuum. The one exception is the lowest-energy peak of F from CHF at 13.4 eV, where its width and lack of structure suggest it may correspond to a direct ion-pair transition
Theoretical prediction of airplane stability derivatives at subcritical speeds
The theoretical development and application is described of an analysis for predicting the major static and rotary stability derivatives for a complete airplane. The analysis utilizes potential flow theory to compute the surface flow fields and pressures on any configuration that can be synthesized from arbitrary lifting bodies and nonplanar thick lifting panels. The pressures are integrated to obtain section and total configuration loads and moments due side slip, angle of attack, pitching motion, rolling motion, yawing motion, and control surface deflection. Subcritical compressibility is accounted for by means of the Gothert similarity rule
CdS solar cell development Final report
Plastic substrate, cadmium sulfide thin film solor cel
3013/9975 Surveillance Program Interim Summary Report
The K-Area Materials Storage (KAMS) Documented Safety Analysis (DSA) requires a surveillance program to monitor the safety performance of 3013 containers and 9975 shipping packages stored in KAMS. The SRS surveillance program [Reference 1] outlines activities for field surveillance and laboratory tests that demonstrate the packages meet the functional performance requirements described in the DSA. The SRS program also supports the complexwide Integrated Surveillance Program (ISP) [Reference 2] for 3013 containers. The purpose of this report is to provide a summary of the SRS portion of the surveillance program activities through fiscal year 2010 (FY10) and formally communicate the interpretation of these results by the Surveillance Program Authority (SPA). Surveillance for the initial 3013 container random sampling of the Innocuous bin and the Pressure bin has been completed and there has been no indication of corrosion or significant pressurization. The maximum pressure observed was less than 50 psig, which is well below the design pressure of 699 psig for the 3013 container [Reference 3]. The data collected during surveillance of these bins has been evaluated by the Materials Identification and Surveillance (MIS) Working Group and no additional surveillance is necessary for these bins at least through FY13. A decision will be made whether additional surveillance of these bins is needed during future years of storage and as additional containers are generated. Based on the data collected to date, the SPA concludes that 3013 containers in these bins can continue to be safely stored in KAMS. This year, 13 destructive examinations (DE) were performed on random samples from the Pressure & Corrosion bin. To date, DE has been completed for approximately 30% of the random samples from the Pressure & Corrosion bin. In addition, DE has been performed on 6 engineering judgment (EJ) containers, for a total of 17 to date. This includes one container that exceeded the 3013 Standard moisture limit which was opened at LANL. The container pieces and an oxide sample were sent to SRNL for examination in FY11. No significant pressurization has been observed for the Pressure & Corrosion bin containers. Relatively minor corrosion has been observed on some convenience containers and the inside of two inner containers. While the limited extent of corrosion does not jeopardize the integrity of the outer 3013 containers, it does highlight the importance of continuing to perform DE and the Shelf Life program to assure that the corrosion rate is not accelerating or changing to a different corrosion mechanism (e.g., stress corrosion cracking). Statistical sampling is currently scheduled to be completed in FY17, but there is a proposed reduction of the number of DE's per year for FY11 and beyond which may delay the completion date. Since 3013 containers are stored inside 9975 containers, surveillances of 9975 containers are performed in conjunction with 3013 container surveillances. Results of 9975 container nondestructive examinations (NDEs) and DEs indicate that the containers will provide adequate protection of the 3013 containers in K-Area storage for at least 15 years [Reference 4]
Krill-feeding behaviour in a chinstrap penguin compared to fish-eating in Magellanic penguins: a pilot study.
Inferring feeding activities from undulations in diving depth profiles is widespread in studies of foraging marine predators. This idea, however, has rarely been tested because of practical difficulties in obtaining an independent estimate of feeding activities at a time scale corresponding to depth changes within a dive. In this study we attempted to relate depth profile undulations and feeding activities during diving in a single Chinstrap Penguin Pygoscelis antarctica, by simultaneously using a conventional time-depth recorder and a recently developed beak-angle sensor. Although failure in device attachments meant that data were obtained successfully from just a part of a single foraging trip, our preliminary results show a linear relationship between the number of depth wiggles and the number of underwater beakopening
events during a dive, suggesting that the relative feeding intensity of each dive could be represented by depth-profile data. Underwater beak-opening patterns of this krill-feeding penguin species are compared with recent data from three fish- and squid-feeding Magellanic Penguins Spheniscus magellanicus
Investigating Heating and Cooling in the BCS & B55 Cluster Samples
We study clusters in the BCS cluster sample which are observed by Chandra and
are more distant than redshift, z>0.1. We select from this subsample the
clusters which have both a short central cooling time and a central temperature
drop, and also those with a central radio source. Six of the clusters have
clear bubbles near the centre. We calculate the heating by these bubbles and
express it as the ratio r_heat/r_cool=1.34+/-0.20. This result is used to
calculate the average size of bubbles expected in all clusters with central
radio sources. In three cases the predicted bubble sizes approximately match
the observed radio lobe dimensions.
We combine this cluster sample with the B55 sample studied in earlier work to
increase the total sample size and redshift range. This extended sample
contains 71 clusters in the redshift range 0<z<0.4. The average distance out to
which the bubbles offset the X-ray cooling in the combined sample is at least
r_heat/r_cool=0.92+/-0.11. The distribution of central cooling times for the
combined sample shows no clusters with clear bubbles and t_cool>1.2Gyr. An
investigation of the evolution of cluster parameters within the redshift range
of the combined samples does not show any clear variation with redshift.Comment: 12 pages, 9 figures, accepted for publication in MNRA
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